The present invention relates to a method and to an apparatus for at least partially wrapping a piece-goods stack, in which a tubular portion is pulled over the piece-goods stack.
Methods and apparatuses of this type are known. What is referred to as a hood stretching method or else a hood shrinking method may be involved. Both methods are distinguished in that a tubular portion consisting of a tubular film is pulled or pushed over any item of freight, referred to below as piece-goods stack, and is brought to bear thereagainst. In this case, the corresponding tubular portions may be in the manner of a hood, i.e. closed at the top, or in the manner of a band, i.e. open at the top. The tubular portions serve in particular to secure the position of the individual item of freight or of the entire piece-goods stack. Thereby, the piece-goods stack can be secured on, respectively at a pallet. However, pallet-free piece-goods stacks which are connected with the aid of the tubular portion to form more easily handleable loading units are also conceivable.
In the shrinking method, use is made of a tubular portion which has a larger diameter than the circumferential extent of the piece-goods stack. Said tubular portion is pulled over the piece-goods stack and shrunk onto the piece-goods stack by means of the action of heat. In the stretching method, use is made of a tube, the diameter of which is smaller than the circumference of the piece-goods stack. The tube is then expanded by suitable stretching means such that it can be pulled or pushed over the piece-goods stack. Solutions are also known, in which the piece-goods stack is pushed into the reefed tubular portion by means of an elevating platform. All of this is intended to be covered by the subject matter of the application. After being drawn over, the tubular portion is released and, by means of the elastic resetting force thereof, keeps the piece-goods stack together or secures the latter at the pallet.
The known stretching or shrinking installations share the problem that the piece-goods stacks consisting of relatively rough and/or stable piece goods, for example cartons, are held relatively well by the particular tubular portion, in particular if the tubular portion is configured in the manner of a hood. However, it has been shown time and again that it would be desirable for the piece-goods stacks to be held together even more strongly, in particular if they involve relatively loose or heavy loads, for example loads of stones, or flexible piece goods, for example beverage bottles made of plastic, in which the beverage does not contain any carbon dioxide. It is specifically loose, heavy and/or flexible piece-goods which need to be secured in position particularly well, this frequently not being possible to obtain in the past in a satisfactory manner using the known packaging methods and packaging apparatuses.